1. Field of the Invention
The present invention relates to a load driver, an image forming apparatus, a load driving method, and a computer program product.
2. Description of the Related Art
As a method used by an image forming apparatus of generating a toner cloud in order to develop an image, there is a method in which pulses of opposite phases are applied to the core metal and the surface electrode of a developing roller. In this method, the core metal and the surface electrode of the developing roller form a capacitive load.
Such application of pulses to both ends of a capacitive load is also used in the field of plasma displays. The problem with load drivers that charge or discharge a capacitive load is large power consumption. A technology to cause an energy transfer by using LC resonance so as to reduce the power consumption is already known. For example, in Japanese Patent Application Laid-open No. 11-338418, in order to reduce the power consumption, a technique using a driving method to apply voltage pulses alternately to both terminals of a capacitive load (a display cell of a plasma-display panel) is proposed in which a capacitive load is divided into two blocks, the voltage phase of each block is shifted, and thus charge is supplied to or released from the capacitive load of each block by making use of resonance.
However, in the method of Japanese Patent Application Laid-open No. 11-338418, while a voltage is applied to one of the capacitive loads, both terminals of the other capacitive load are equipotential. That is, voltage pulses of opposite phases cannot be applied to both ends of a capacitive load. In cloud development, a toner cloud is generated by applying voltage pulses of opposite phases to both ends of a capacitive load, and therefore, conventional methods, such as that of Document 1, cannot be applied to cloud development.